For well-known electrostatic precipitators at present, corona discharge electrode lines and dust-collecting electrode plates which form a plurality of sedimentation passages are mounted in a casing. The negative DC high voltage electricity is applied to the corona discharge electrode lines to discharge negative electric ions which are used for charging dust particles contained in the dust-laden airflow electrically. While, the positive DC high voltage electricity is applied to the dust-collecting electrode plates to collect the negative dust particles charged electrically. Then, the vibration apparatus vibrates the dust particles collected from the dust-collecting electrode plates down to the hoppers at the lower part of the precipitators and accordingly the removal of dust particles in the airflow can be achieved.
However, precipitators of this kind have extremely poor efficiency on removing sub-micron-sized dust particles contained in the dust-laden airflow. Furthermore, when the dust is cleaned by vibration, a part of the dust is always discharged out with airflow due to the flying dust for the second time by vibration. Accordingly, the efficiency of the precipitators becomes instable and the concentration of dust particles in the exhaust air always stays high.
According to related national standards, the discharge concentration of the industrial dust is controlled at 50 mg/m3 according to the most advanced dust removing technologies at present. However, this standard has no limitation on the discharge control of sub-micron-sized dust, which is really harmful to the health of human beings. At present, in China, more than 8 million tons of the sub-micron-sized aerosol dust is discharged into the air each year. Because it is very difficult for sub-micron-sized aerosol dust particles to settle, after the accumulation, they make air pollution more and more severe. According to the current conditions of the air environmental protection in China, in order to remove harmful substances in the air effectively and to get blue sky back fundamentally, the concentration of sub-micron-sized aerosol in the air discharged from all mines, factories and enterprises needs to be controlled below 1 mg/m3. However, dust removers in the present market can never remove sub-micron-sized aerosol particles in industrial dust.